JP2019114446A - Micro heater with non-heating part - Google Patents

Abstract

To solve the problem in which, in a micro heater having a non-heating part, a decrease in a diameter of a wire produced at a welding portion with a heating wire of a non-heating wire sometimes causes disconnection at a time of use, and to provide a micro heater having a non-heating part without a decrease in a diameter of the non-heating wire.SOLUTION: In a micro heater in which a heating wire 4 is accommodated with an inorganic insulating material powder 6 interposed in a metal sheath tube 3, a metal having a lower electrical resistivity than a material of the heating wire 4 is plated 5 on a surface of the heating wire 4 to form a non-heating wire. Since there is no welded portion between the heating wire 4 and the non-heating wire in the micro heater 1 having the non-heating part, there is no reduction in a diameter of the non-heating wire that causes disconnection.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a microheater having a non-heat generating portion among microheaters in which an inorganic insulating material powder is interposed in a metal sheath and a heating wire generating Joule heat by energization is accommodated.

  The micro-heater is a flexible heater containing an inorganic insulating material powder in a metal sheath and containing a heating wire that generates Joule heat when energized. The basic structure is shown in FIGS. 4 and 5. There are two types. FIG. 4 is a cross-sectional view showing a basic first configuration of the conventional micro heater, and FIG. 5 is a cross-sectional view showing a basic second configuration of the conventional micro heater.

  4 (a) and 5 (a) are cross-sectional views in the longitudinal direction, and FIGS. 4 (b) and 5 (b) are cross-sectional views taken along the line E-E in FIG. 4 (a), and FIG. It is a figure of the FF cross section of. However, the terminal sleeve 7 and the insulation coatings 13 and 15 of the lead wires 80 and 81 for supplying electricity are drawn in an outer shape, and in order to make it easy to see, FIG. 4 (b) and FIG. a) is drawn at a larger scale than FIG.

  In the micro heater 10 shown in FIG. 4, the heating wire 4 is accommodated in the metal sheath tube 3 with the inorganic insulating material powder 6 interposed, and the end sleeve 7 is provided at both ends thereof. The conductors 14 and 16 exposed from the insulation coatings 13 and 15 of the lead wires 80 and 81 are connected thereto. In the metal outer frame of the end sleeve 7, the end of the heating wire 4 and the ends of the conductors 14, 16 are connected, and moisture does not infiltrate into the inorganic insulating material powder 6 to prevent the insulation resistance from decreasing. A seal is provided.

  Unlike the microheater 10 of FIG. 4, the microheater 20 shown in FIG. 5 has the heat-generating wire 4 that reciprocated is accommodated in the metal sheath tube 3 with the inorganic insulating material powder 6 interposed therebetween. Is provided only on one side. The role of the end sleeve 7 is the same as that of the end sleeve 7 of FIG. 4, and the ends of the heating wire 4 and the ends of the conductors 14, 16 exposed from the insulation coatings 13, 15 of the lead wires 80, 81 in the metal outer frame , And a seal is provided so that moisture does not infiltrate the inorganic insulating material powder 6 and the insulation resistance is not reduced.

  As a material of the heating wire 4 of the micro heaters 10 and 20 of FIGS. 4 and 5, nichrome having a large electric resistance and a large amount of heat generation is used except for a special exception.

  The specific structure of the inside of the end sleeve 7 in FIGS. 4 and 5 is representative of that shown in FIG. 1 of Patent Document 1 by the same applicant as the present patent application. As shown in the figure, the end of the heating wire (22) and the conductor (13) of the lead wire in the metal outer frame (11) interpose an insulating material (14, 17). The seal is housed in the outer frame (code 11), and a seal (code 15) is provided at the end of the metal outer frame (code 11). In each end sleeve 7 in the structure of FIG. 4, the heating wire (code 22) and the conductor (code 13) of FIG. 1 of Patent Document 1 are one each. Here, the reference numerals in parentheses are the reference numerals shown in FIG. 1 of Patent Document 1.

  When the object to be heated and the end seal are separated, for example, when the object to be heated is inside the container, the terminal sleeve 7 of FIG. 4 and FIG. 5 is usually placed outside the container and the heating wire 4 and the inorganic insulating material powder are separated. A metal sheath 3 containing 6 is laid in the container to the object to be heated. In this case, in the microheaters 10 and 20 of FIGS. 4 and 5 in which the heating wire 4 is provided over the entire length in the metal sheath tube 3, the portions not requiring heating are also heated, and the microheaters 10 and 20 are unnecessary. Power consumption, and other problems such as damage to the device by heating the device in the container having a low heat-resistant temperature other than the heating target.

  In order to avoid such an adverse effect when the object to be heated is separated from the end seal, conventionally, only the portion heated in contact with the object to be heated generates heat, and the other portions do not generate heat, as shown in FIG. In many cases, the micro heaters 11 and 21 shown in 7 are used. FIG. 6 is a cross-sectional view showing a first basic configuration of a conventional microheater having a non-heat generation portion, and FIG. 7 is a cross-sectional view showing a second basic configuration of a conventional microheater having a non-heat generation portion 6 and 7 show the outer sleeves 13 and 15 of the end sleeve 7 and the lead wires 80 and 81 in the same manner as in FIGS. 4 and 5, respectively.

  In the microheaters 10 and 20 shown in FIGS. 4 and 5, the heating wire 4 made of nichrome, which has a high electrical resistivity, generates heat over the entire length, whereas the microheaters 11 and 21 in FIGS. A heat generating portion in which a heat generating wire 4 made of nichrome wire is accommodated, a non-heat generating portion in which a non-heat generating wire 17 made of copper having a small amount of heat generation due to a small electrical resistivity is accommodated, and an alloy of nichrome and copper It can be divided into an intermediate heating portion in which the portion 18 exists. The same components as those of the microheaters 10 and 20 of FIGS. 4 and 5 except that the non-heating wire 17 and the alloy portion 18 are present, the same components are shown in FIGS. 6 and 7 using the same reference numerals. .

  In the micro-heaters 11 and 21 of FIGS. 6 and 7, by setting only the portion that contacts and heats the heating target as the heating portion, unnecessary power consumption is suppressed, and damage to the device due to unnecessary heating is avoided. be able to.

  A portion shown in FIGS. 4 to 7 in which the metal sheath tube 3 has the inorganic insulating material powder 6 interposed and a metal wire such as the heating wire 4 and the non-heating wire 17 is accommodated is often called a microheater cable. Hereinafter, the micro heater cable refers to this part. As shown in FIGS. 7 and 8 of Patent Document 2, a micro-heater cable is first made thicker than the finished diameter, and the diameter is reduced by die drawing or swaging to make a predetermined diameter shown in FIG. 6 of the same document. Finished in diameter micro heater cable.

  In the micro-heater with non-heat generation part shown in FIGS. 6 and 7, the metal wire accommodated when making a micro cable thicker than the finished diameter before diameter reduction is at both ends of the heating wire 4 thicker than the finished diameter made of nichrome. The non-heating wire 17 made of copper having substantially the same diameter is butt welded.

  In the butt welding of the heating wire 4 and the non-heating wire 17, an alloy portion of nichrome which is the material of the heating wire 4 and copper of the material of the non-heating wire 17 inevitably occurs, and this alloy portion is stretched after diameter reduction The alloy portion 18 is formed, and the portion where the portion exists is an intermediate heat generation portion having an intermediate resistance between nichrome and copper.

  In addition, even if it is a copper wire, generation | occurrence | production of Joule heat is not zero. Since the calorific value per unit length is proportional to the square of the applied current and the resistance value per unit length, the calorific value per unit length of two types of connected wires through which the same current flows is per unit length Proportional to the resistance value of If the two types of wires have the same diameter, the resistance per unit length is proportional to the electrical resistivity, and the calorific value per unit length is proportional to the electrical resistivity. In the non-heat generating portion of FIGS. 6 and 7, since the electrical resistivity of copper is about 1.6% of nichrome, the calorific value per unit length is about 1 of the calorific value per unit length of the calorific part. It is .6%. As described above, even in the non-heating wire and the non-heating portion, heat is generated although it is smaller than the heating wire and the heating portion. Also in the following, a heating wire and a wire and a portion whose heat generation is smaller than that of the heating portion are respectively referred to as a non-heating wire and a non-heating portion.

JP, 2010-257582, A JP, 2017-112079, A

  As well known, welding of dissimilar metals is difficult. As described above, in the conventional microheater having a non-heating portion shown in FIGS. 6 and 7, it is necessary to perform butt welding before reducing the diameter of the heating wire 4 made of nichrome and the non-heating wire 17 made of copper. is there.

  In this butt-welded portion, a bulge of the alloy portion 18 and a recess 22 of the non-heating wire 17 often occur as shown in FIG. The cause of this is that the melting point of copper is lower than that of nichrome, and the thermal conductivity of copper is high. During butt welding, copper melts extensively before it is raised to the melting point of nichrome, and copper melted by surface tension Still move to the solid nichrome side, and after welding, the non-heat-generating wire 17 side of the alloy portion 19 swells around the entire circumference, ie, the shape shown in FIG. It is considered that a dent 23 is formed on the entire circumference near the boundary, and when this diameter is reduced to the finished diameter, the swelling of the alloy portion 18 and the dent 22 of the non-heating line 17 in FIG.

  Because the thermal expansion coefficient of the nichrome heating wire 4 and copper non-heating wire 17 is different from the thermal expansion coefficient of the inorganic insulating material powder 6 and the metal sheath tube 3, the heating wire 4 and non-heating wire 17 when using the microheater There is tension and compressive stress on the surface. This stress is particularly large at the time of temperature rise when the temperature difference with the metal sheath tube 3 becomes large, and at the time of temperature decrease, and when raising and lowering the temperature is repeated, the recess 22 of the non-heating wire 17 of copper is generated and the diameter is narrowed. There is a problem that the conventional microheater with non-heating part has a problem that disconnection may occur.

  As a countermeasure against this problem, a nickel-based alloy wire, a copper-based alloy wire, or a copper-based alloy wire having an intermediate thermal conductivity or melting point of copper and nichrome in a conventional microheater having a non-heat generation portion In some cases, a wire in which copper is clad with nickel is used as a relay wire of the heating wire and the non-heating wire. In this case, the short relay wire is butt-welded to the heating wire made of nichrome, and the non-heating wire of copper is butt-welded to the relay wire, so the depression of the non-heating wire is reduced. However, the depression does not disappear at all, and the problem of disconnection can not be completely solved. Moreover, in this method, the electrical resistivity of the relay wire is usually an intermediate value between nichrome and copper, so the relay wire becomes the intermediate heat generation portion shown in FIGS. 6 and 7 and the intermediate heat generation portion becomes longer. A problem arises. When the intermediate heating portion becomes longer, unnecessary power consumption in this portion is increased, and there is an additional problem that the possibility of heating a portion not to be heated is increased.

  The present invention has been made in view of the problem of disconnection caused by the depression of the non-heating wire caused by welding of dissimilar metals in a conventional micro-heater having the non-heating region, and the non-heating portion has no recess in the non-heating line. It aims at providing a certain micro heater.

(First aspect)
The micro-heater with non-heating part according to the invention is
In a microheater in which a heating wire made of metal that generates Joule heat by energization is contained in a metal sheath tube, and inorganic insulating material powder is filled between the metal sheath tube and the heating wire,
The metal of the material whose electric resistivity is lower than the material of the heating wire is plated on the whole surface circumferential direction for a part of the heating wire, and it is a plated heating wire whose calorific value is less than that of the unplated heating wire. It is characterized in that the existing portion is a non-heat generating portion.

  Since the electrical resistivity is lower than the unplated portion, generation of Joule heat is suppressed, and the plated portion becomes a non-heating portion.

  In the micro-heater having a non-heating portion according to the present invention, as in the prior art, butt welding between the heating wire and the non-heating wire is not performed, there is no dent of the non-heating wire generated in butt welding, and disconnection due to the dent It does not occur. In addition, since the butt welding of the heating wire and the non-heating wire is not performed, there is no alloy portion between the heating wire and the non-heating wire, so that the intermediate heating portion does not exist significantly and there is no wasteful power consumption there.

(Second aspect)
In the above-described micro-heater having a non-heating portion, the material of the heating wire is preferably nichrome, and the material of the metal plating the surface of the heating wire is preferably copper.

  With such a material, the calorific value of the heating wire which is not plated becomes equivalent to that of the conventional micro-heater, and the material of the plating is copper having a low electrical resistivity, so that the heat generation of the non-heating portion is generated. The amount can be suppressed efficiently.

(Third aspect)
In a micro-heater with a non-heat generation portion in which the material of this heat generation wire is nichrome and the material of plating is copper, the thickness of the metal plating the surface of the heat generation wire is 3.5% or more of the outside diameter of the heat generation wire. It is desirable that the thickness of the

  As described above, the calorific value per unit length is proportional to the resistance per unit length. The resistance value of the line plated with copper on the surface of the nichrome wire can be determined as the resistance of a circuit in which the resistance of the nichrome wire and the resistance of the copper plating are connected in parallel, and the electrical resistivity of copper is about 1 of nichrome. .6% and the resistance value per unit length is the value obtained by dividing the electrical resistivity by the cross-sectional area, a unit of copper plated Nichrome wire of the same diameter as the heating wire When the resistance value per length is determined, when the thickness of copper plating is 3.5% of the diameter of the heating wire made of nichrome, the unit of the non-heating portion where the plated portion exists The resistance value per length is 10% of the resistance value per unit length of the heat generating portion where the non-plated heat generating wire exists.

  Therefore, by setting the thickness of plated copper to 3.5% or more of the outer diameter of the heat generating wire, the heat generation amount per unit length of the non-heat generation portion can be calculated as the heat generation amount per unit length of the heat generation portion It can be suppressed to 10% or less of

(Fourth aspect)
Furthermore, in the micro-heater with a non-heating part where the material of the heating wire is nichrome and the material of the plating is copper, the thickness of the metal plating the surface of the heating wire is 20% or more of the outer diameter of the heating wire. It is more desirable to be thick.

  When the thickness of the plated copper is 20% of the outer diameter of the heating wire, the resistance value per unit length of the non-heating portion is determined in the same manner as described above. Is about 1.6% of the resistance per unit length, which is equivalent to the resistance per unit length of the conventional copper non-heating wire.

  Therefore, by setting the thickness of the plated copper to 20% or more of the outer diameter of the nichrome heating wire, the heat generation amount per unit length of the non-heat generation portion with respect to the heat generation amount per unit length of the heat generation portion The conventional copper can be made equal to or less than about 1.6% of the non-heating wire material. As the calorific value of the non-heat generating portion is reduced, unnecessary power consumption is eliminated, and heating of a portion where heating is unnecessary is also reduced.

  The outer diameter of the part called the micro heater cable containing the heating wire and the plated part with the inorganic insulating material powder interposed in the metal sheath is 1.6 mm to 6 mm. The outer diameter of the nichrome heating wire is generally 0.25 mm to 1.25 mm. When the thickness of the copper plating is 20% of the heating wire outer diameter, the plating thickness is 0.25 mm for the φ1.25 mm heating wire.

  Here, also in the production of the micro heater cable having a non-heat generating portion according to the present invention, as in the prior art, a thicker one than the finished diameter is first made, and this is diameter reduced by die pulling or swaging to make a micro heater cable of a predetermined diameter. Finished. In the case of a microheater having no non-heating portion, the diameter reduction ratio is reduced to make a long microheater cable, which is cut to manufacture a large number of microheaters. On the other hand, in a microheater with non-heat generation part, the position of the heat generation part differs depending on the location used, and since there are heat generation part and non-heat generation part, a long micro heater cable is cut to Since the heater can not be manufactured, the diameter reduction ratio is usually about one half to one third, and the diameter reduction ratio of the microheater having a non-heat generating part according to the present invention is also about the same. In order to set the plating thickness of copper at the finished diameter to 0.25 mm, the thickness of the copper plating before the diameter reduction is 0.5 mm, with the diameter reduction ratio being 1/2, and the diameter reduction ratio is 1/3. Although 0.75 mm is required, this thickness is a thickness that can be plated with copper without special difficulties.

  As described above, according to the microheater having a non-heating portion according to the present invention, there is no reduction in the diameter of the non-heating wire due to the depression near the welding portion with the heating wire which has conventionally occurred. There is no concern that there will be disconnection. In addition, it has an additional effect that there is no unnecessary intermediate heat generation portion generated in the weld between the heat generation wire and the non-heat generation wire, which has conventionally been.

Sectional drawing which shows 1st Embodiment of the micro heater with the non-heating part by this invention Sectional view showing a second embodiment of the micro-heater with non-heating part according to the present invention Sectional drawing which shows the boundary part of the heating line and non-heating line in 1st Embodiment of this invention. Sectional view showing a basic first configuration of a conventional micro heater Sectional view showing a basic second configuration of a conventional micro heater Sectional view showing a basic first configuration of a conventional microheater having a non-heat generating portion Sectional view showing a second basic configuration of a conventional microheater having a non-heating portion Sectional drawing which shows the boundary part of the heating line and non-heating line in the basic 1st structure of the microheater with the conventional non-heating part

  The first and second two embodiments for carrying out the present invention will be described.

First Embodiment
FIG. 1 is a cross-sectional view showing a first embodiment of a microheater having a non-heating portion according to the present invention, FIG. 1 (a) is a longitudinal cross-sectional view, and FIGS. 1 (b) and (c) are each a diagram It is an AA cross section and a BB cross section of 1 (a). However, the end sleeve 7 of FIG. 1 (a) and the insulation coatings 13 and 15 of the lead wires 80 and 81 are drawn in external form, and in order to make them easy to see, FIGS. It is drawn at a large scale. Further, in the figures, the components having the same functions as those of the conventional micro-heater shown in FIGS. 4 to 7 have the same reference numerals as those in FIGS. 4 to 7, and the same applies to FIG. It is.

  In the microheater 1 having the non-heat generating portion according to the first embodiment, the inorganic insulating material powder 6 is interposed in the metal sheath pipe 3 and made of metal and the heating wire 4 generating Joule heat by energization is accommodated. The heating wire 4 has a portion on the surface of which the plating 5 made of a metal having a lower electrical resistivity than the material of the heating wire 4 is made, and the portion on which the plating 5 is made becomes a non-heating wire. There is. Since the electric resistivity of the portion plated is smaller than that of the portion not plated, generation of Joule heat is suppressed to become a non-heating line, and this portion becomes a non-heating portion. Further, the portion where the plating 5 is not formed is a regular heat generation and becomes a heat generation portion.

  End sleeves 7 are provided at both ends of the metal sheath 3, the inorganic insulating material powder 6, and the metal sheath 3, and the terminal sleeve 7 is provided with insulating coatings 13 and 15 of lead wires 80 and 81 for energization. The structure in which the exposed conductors 14 and 16 are connected is the same as that of the conventional non-heat generating microheater 11 shown in FIG. In addition, as for the structure in the end sleeve 7, the heating wire shown by the code 22 in FIG. 1 of FIG. 1 by the same applicant as the present patent application and the conductor shown by the code 13 are respectively one. It is a structure.

  In the microheater 1 having this non-heat generation portion, butt welding of the heating wire and the non-heating wire is not performed as in the prior art, there is no dent of the non-heating wire generated in butt welding, and disconnection occurs due to the dent. do not do. Further, since there is no alloy portion between the heating wire and the non-heating wire, the intermediate heating portion does not significantly exist, and there is no wasteful power consumption there.

  With regard to the material used, the material of the heating wire 4 in this embodiment is nichrome, and the material of the plating 5 is copper. As a material of the heat generating wire 4, nichrome having a high electric resistivity and a large heat generation amount is conventionally used, and also in the present embodiment, the heat generation amount of the heat generating portion is conventionally changed by using nichrome for the material of the heat generating wire 4. It is equivalent to the micro heater. Further, by setting the material of the plating 5 to copper having a low electrical resistivity, the amount of heat generation of the non-heat generating portion is efficiently suppressed.

  The other material of this embodiment is that the metal sheath tube 3 is SUS316 and the inorganic insulating material powder 6 is magnesia. Of course, the materials of the heating wire 4, the plating 5, the metal sheath tube 3 and the inorganic insulating material powder 6 are limited to these as long as the electrical resistivity of the material of the plating 5 satisfies the condition lower than the material of the heating wire 4. The material may be changed depending on the use conditions such as temperature, not the temperature.

  Regarding the cross-sectional shape, the outer diameter of the metal sheath tube 3 of this embodiment is 3.2 mm, the inner diameter is 2.56 mm, the outer diameter of the heating wire 4 is 0.77 mm, and the thickness of the plating 5 is 0.16 mm. The outer diameter of the heating wire is 1.09 mm. The inner diameter of the metal sheath tube 3 and the outer diameter of the heating wire 4 are respectively the same as the microheater 10 of the conventional metal sheath tube 3 shown in FIG. 4 with an outer diameter of 3.2 mm and the conventional metal sheath shown in FIG. Match the standard inner diameter of the metal sheath tube 3 and the standard outer diameters of the heating wire 4 and the non-heating wire 17 of the microheater 11 with the non-heating part of the outer diameter of the tube 3 of 3.2 mm. There is.

  The calorific value per unit length is proportional to the resistance per unit length. The resistance of the non-heating wire made of copper plating 5 with a thickness of 0.16 mm, that is, about 20% of the outer diameter of heating wire 4 on the surface of heating wire 4 with an outer diameter of 0.77 mm made of nichrome The value can be determined as the resistance of the circuit in which the resistance of the nichrome wire and the resistance of the copper plating are connected in parallel, the electrical resistivity of copper being about 1.6% of nichrome, and the value per unit length The resistance value is about 1.6% of the resistance value of the heating wire 4 when the resistance value per unit length of the non-heating wire is determined using the resistance value divided by the cross-sectional area. Is equivalent to the resistance value per unit length of the conventional non-heating wire made of copper having an outer diameter of 0.77 mm. Therefore, the calorific value per unit length of the non-heat generating portion with respect to the calorific value per unit length of the heating wire 4 of the present embodiment is equivalent to about 1.6% of that in the case of the conventional copper non-heating line. .

  If the thickness of the plating 5 is increased, the calorific value of the unit length of the non-heating line which is the plated 5 is further reduced, and if the thickness of the plating 5 is reduced, the unit length of the non-heating line The calorific value of is increased. In the present embodiment, when the thickness of the plating 5 is 0.03 mm, that is, about 3.5% of the outer diameter 0.77 mm of the heating wire 4, the calorific value per unit length of the non-heating wire is the heating wire. Can be reduced to about 10%.

  Also in the present embodiment, as in the prior art, in the production of a portion referred to as a microheater cable in which the heating wire 4 and the plated portion 5 are accommodated with the inorganic insulating material powder 6 interposed in the metal sheath tube 3. As in the above, first, a thicker one than the finished diameter is first made, and the diameter is reduced to a half to a third by die drawing or swaging to obtain a microheater cable having an outer diameter of 3.2 mm. In the present embodiment, when the diameter reduction ratio is 1/2, the outer diameter of the metal sheath tube 3 before the diameter reduction is 6.4 mm, the outer diameter of the heating wire 4 is about 1.5 mm, and the thickness of the copper plating 5 In the case of one third, the outer diameter of the metal sheath tube 3 before diameter reduction is 9.6 mm, the outer diameter of the heating wire 4 is about 2.3 mm, and the plating of copper 5 is The thickness is about 0.47 mm.

  FIG. 3 is a cross-sectional view showing the boundary between the heating wire and the non-heating wire in the first embodiment of the present invention, and FIG. 3 (a) is a cross-sectional view before diameter reduction at the time of manufacturing the microheater cable; FIG. 3 (c) is an enlarged view of the boundary between the reduced diameter heating wire 4 and the non-heating wire plated with copper 5 surrounded by a chain line in FIG. 3 (b). As shown in FIG. 3 (a), the portion plated with copper 5 and the portion only with heating wire 4 not plated 5 are clearly separated because there is no alloy portion as in the prior art, Even if the diameter is reduced as shown in FIG. 3 (b), as shown in FIG. 3 (c), the range of the portion corresponding to the intermediate heating portion in FIG. Existence of exothermic part is equal to none.

Second Embodiment
FIG. 2 is a cross-sectional view showing a second embodiment of the microheater having a non-heating portion according to the present invention, FIG. 2 (a) is a longitudinal cross-sectional view, and FIGS. 2 (b) and 2 (c) are each a diagram It is a CC cross section of 2 (a), and a DD cross section. However, the end sleeve 7 of FIG. 2 (a) and the insulation coatings 13 and 15 of the lead wires 80 and 81 are drawn in external form, and in order to make it easy to see, FIGS. It is drawn at a large scale. Further, in the drawings, the components having the same functions as those of the conventional micro-heater shown in FIGS. 4 to 7 are denoted by the same reference numerals as those in FIGS. 4 to 7.

  In the microheater 2 having the non-heat generating portion according to the second embodiment, the inorganic insulating material powder 6 is interposed in the metal sheath pipe 3 and made of metal and the heating wire 4 generating Joule heat by energization is accommodated. The heating wire 4 has a portion on the surface of which the plating 5 made of a metal having a lower electrical resistivity than the material of the heating wire 4 is made, and the portion on which the plating 5 is made becomes a non-heating wire. This is the same as the first embodiment. Since the electric resistivity of the portion plated is smaller than that of the portion not plated, generation of Joule heat is suppressed to become a non-heating line, and this portion becomes a non-heating portion. Further, the portion where the plating 5 is not formed generates a regular heat and becomes a heat generating portion as in the first embodiment.

  A terminal sleeve 7 is provided at the end of the metal sheath tube 3, the inorganic insulating material powder 6, and the metal sheath tube 3 other than this non-heating wire, and lead wires 80 and 81 for energizing the terminal sleeve 7. The structure in which the conductors 14 and 16 exposed from the insulating coatings 13 and 15 are connected is the same as that of the conventional microheater 21 having a non-heating portion shown in FIG. The structure in the end sleeve 7 is the structure shown in FIG. 1 of Patent Document 1.

  The materials of the heating wire 4, the plating 5, the metal sheath tube 3 and the inorganic insulating material powder 6 are the same as in the first embodiment. If the electrical resistivity of the material of the plating 5 satisfies the conditions lower than the material of the heating wire 4, the invention is not limited to these, and the material may be changed according to the use conditions as in the first embodiment. .

  Regarding the cross-sectional dimensions, the outer diameter of the metal sheath tube 3 of this embodiment is 3.2 mm, the inner diameter is 2.56 mm, the outer diameter of the heating wire 4 is 0.31 mm, and the thickness of the plating 5 is 0.07 mm, The outer diameter of the non-heating wire is 0.45 mm. The inner diameter of the metal sheath tube 3 and the outer diameter of the heating wire 4 are respectively the same as the microheater 20 of the conventional metal sheath tube 3 shown in FIG. 5 with an outer diameter of 3.2 mm and the conventional metal sheath shown in FIG. Match the standard inner diameter of the metal sheath tube 3 and the standard outer diameters of the heating wire 4 and the non-heating wire 17 of the microheater 21 with the non-heating part of the outer diameter of the tube 3 of 3.2 mm. There is.

  When the resistance value per unit length of the non-heating wire is determined, the second embodiment is also about 1.6% of the resistance value of the heating wire 4 as in the first embodiment, which corresponds to the conventional outer diameter of 0.31 mm. Is equivalent to the resistance value per unit length of copper non-heating wire. Therefore, also in the present embodiment, the calorific value per unit length of the non-heat generating part with respect to the calorific value per unit length of the heating line 4 is equivalent to about 1.6% of the case of the conventional copper non-heating line. .

  If the thickness of the plating 5 is increased, the calorific value of the unit length of the non-heating line which is the plated 5 is further reduced, and if the thickness of the plating 5 is reduced, the unit length of the non-heating line The calorific value of is also the same as in the first embodiment. In the second embodiment, when the thickness of the plating 5 is 0.01 mm, that is, about 3.5% of the outer diameter 0.31 mm of the heating wire 4, the calorific value per unit length of the non-heating wire is It can be suppressed to about 10% of the heating wire.

  Also in this embodiment, as in the first embodiment and the prior art, in the manufacture of the microheater cable, first, one thicker than the finished diameter is first made and the diameter is halved to one third by die pulling or swaging. The diameter is reduced to a micro heater cable with an outer diameter of 3.2 mm. In the present embodiment, in the case of a half diameter reduction rate, the outer diameter of the heating wire 4 before the diameter reduction is 6.4 mm, the thickness of the copper plating 5 is about 0.13 mm, and a third In this case, the outer diameter of the heating wire 4 before diameter reduction is 9.6 mm, and the thickness of the copper plating 5 is about 0.19 mm.

  Since there are no alloy parts as in the prior art, the heating wire 4 and the non-heating wire are clearly separated in the micro-heater cable before the diameter reduction. The form is also the same as in the first embodiment.

  As described above, although the finished diameter of the microheater cable in the two embodiments, that is, the outer diameter of the metal sheath tube 3 is 3.2 mm, the mainstream of the microheater cable conventionally used in the industry is as described above. The microheater cable of the microheater having a non-heating part according to the present invention may have the same outer diameter as before, according to the outer diameter, the diameter of the heating wire 4, plating The thickness of 5 is changed. As described above, the thickness of the copper plating 5 is not limited in the range of the outer diameter of the metal sheath tube 3.

  The total length of the microheater cable and the position and length of the heat generating part are determined by the distance between the end sleeve and the object to be heated, the size of the object to be heated, etc. Absent.

1 Micro heater with non-heating part (1st embodiment)
2 Micro-heater with non-heating part (2nd embodiment)
Reference Signs List 3 metal sheath tube 4 heating wire 5 plating 6 inorganic insulating material powder 7 end sleeve 80, 81 lead wire 13, 15 lead wire insulation coating 14, 16 lead wire conductor

(First aspect)
The micro-heater with non-heating part according to the invention is
In a microheater in which a heating wire made of metal that generates Joule heat by energization is contained in a metal sheath tube, and inorganic insulating material powder is filled between the metal sheath tube and the heating wire,
A metal of a material whose electric resistivity is lower than that of the heating wire is plated on the entire surface circumferential direction on a part of the heating wire, and the amount of heat generation is smaller than that of the unplated heating wire. It is characterized in that the portion where the generated heating wire exists is a non-heating portion.

Claims (4)

In a microheater in which a heating wire made of a metal that generates Joule heat when energized is accommodated in a metal sheath tube, and inorganic insulating material powder is filled between the metal sheath tube and the heating wire,
A metal of a material having a lower electrical resistivity than the material of the heating wire is plated on the entire surface circumferential direction on a part of the heating wire, and the amount of generated heat is smaller than that of the non-plated heating wire. A micro-heater having a non-heating portion, wherein the portion where the heating line exists is a non-heating portion. The material of the heating wire is nichrome,
The micro-heater with non-heat generating portion according to claim 1, wherein a material of a metal plating the surface of the heat generating wire is copper.   3. The micro-heater having a non-heating portion according to claim 2, wherein the thickness of the metal plating the surface of the heating line is 3.5% or more of the outer diameter of the heating line. 4. The micro-heater having a non-heating portion according to claim 3, wherein the thickness of the metal plating the surface of the heating line is 20% or more of the outer diameter of the heating line.

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